NPD data shows that the iPhone, backed by its release on Verizon in the US, actually reversed the market share growth of Android for the first time in two years. This news comes amid mixed information about CDMA iPhones. Reports surfaced today that CDMA iPhone production was cut in half, yet Android-heavy Sprint said the Verizon iPhone had materially impacted its own sales.

Android still did account for half of all US sales, however.

According to NPD’s “Mobile Phone Track” consumer tracking service, for the first time a majority (54 percent) of all new mobile-phone handsets purchased by U.S. consumers were smartphones. Driven by increases in smartphone sales in Q1 2011, average selling prices for all mobile phones rose 2 percent over the previous quarter to reach $102; however, average prices for smartphones actually declined by 3 percent (falling to $145).

The Android OS lost ground for the first time since Q2 2009, falling to 50 percent of smartphone unit sales in Q1 2011 compared to 53 percent in the prior quarter. Apple iOS share rose 9 percentage points to comprise 28 percent of smartphone unit sales. BlackBerry OS also lost ground, falling 5 points, to 14 percent.

“The rise of Apple and HTC show how companies can drive change in a mature device market to change the rules of the game,” said Rubin. “The overall success of U.S. market leaders Samsung and LG will be tied to their success in the smartphone market.”

It appears that the US smartphone race is coming down to two horses.

Perhaps the white iPhone will keep the momentum going in the next quarter?